Rectangular-Shaped Polyaniline Tubes Covered with Nanorods and their Electrorheology

Nanorod covered polyaniline (PANI) tubes with rectangular cross section are synthesized via a chemical oxidation polymerization method and then utilized as an electrorheological (ER) material by dispersion in silicone oil, resulting in 10 vol% particle concentration. These PANI tubes are chosen based on the fact that the PANI is a promising suspension material for ER fluids due to its high polarizability and controllable conductivity. The ER performances are investigated as a function of electric field strength by using a rheometer, and the frequency dependences of permittivity and dielectric loss factor of ER fluids are also measured with a LCR meter. The sedimentation observation is further examined as a function of time, demonstrating improved dispersion stability compared to general particulate PANI-based ER fluid.